Effect of the 21-aminosteroid on nuclear factor-kappa B activation of Kupffer cells in endotoxin shock

Background. The 21-aminosteroid (U-74389G) is a nonglucocorticoid steroid t hat was synthesized to inhibit lipid peroxidation without the glucocorticoi d activity. We recently demonstrated that the 21-aminosteroid administered to endotoxin shock mice reduces liver injury and improves the survival rate of mice through inhibition of nuclear factor-kappa B activation in the liv er The study was undertaken to determine whether the 21-aminosteroid could suppress pro-inflammatory gene up-regulation through inhibition of nuclear factor-kappa B activation in Kupffer cells. Methods. Kupffer cells were isolated from rats by collagenase perfusion fol lowed by pronase digestion. After a lipopolysaccharide addition each assay was performed for tumor necrosis factor-alpha, interleukin-6, tumor necrosi s factor-alpha messenger RNA, nuclear factor-kappa B, and I kappa B protein s. Results. After the lipopolysaccharide addition, Kupffer cells released both tumor necrosis factor-alpha. and interleukin-6. The 21-aminosteroid treatm ent suppressed the release of tumor necrosis factor-alpha in a dose-depende nt manner The 21-aminosteroid also inhibited the increase of tumor necrosis factor-alpha messenger RNA expression and nuclear factor-kappa B activatio n in Kupffer cells 1 hour and 30 minutes, respectively, after lipopolysacch aride addition. Furthermore, the 21-aminosteroid treatment suppressed the d egradation of I kappa B proteins in lipopolysaccharide-stimulated Kupffer c ells. Conclusions. These results suggest that the 21-aminosteroid inhibits releas e of the tumor necrosis factor-alpha and interleukin-6 from lipopolysacchar ide-stimulated Kupffer cells by inhibiting nuclear factor-kappa B activatio n. This is accomplished by inhibiting I kappa B degradation in endotoxin sh ock and this may prove useful for the treatment of endotoxin shock.